利用DIRECTOR4.0开发多媒体教学软件

利用ＤＩＲＥＣＴＯＲ４．０开发多媒体教学软件王宪功，李文光为了更加有效的开发出高质量的教学软件，中央电教馆推荐了ＭＡＣＲＯＭＥＤＩＡ公司开发的ＤＩＲＥＣＴＯＲ４．０作为多媒体创作工具。在软件开发的过程中，我们亲身体会到ＤＩＲＥＣＴＯＲ４．０的强大功能...     

植物隐花色素及其功能研究进展

隐花色素是植物感受外界环境变化的重要光受体之一,近年来的研究揭示其广泛存在于植物中。隐花色素为一类黄素蛋白,在蓝光和近紫外光下能够抑制植物胚轴、胚芽鞘等的伸长,调控植物开花时间、生物钟及气孔开放等。此外,隐花色素在感知磁场、细胞凋亡等方面也有调节作用。     

相似三角形中的“A”型图和“X”形图的应用

在平行线分线段成比例定理中有两种基本图形：“Ａ”型图（图１）和“Ｘ”型图（图２）．它们都是由ＤＥ∥ＢＣ而构成比例线段,在解题中有着重要的作用．下面谈谈相似三角形中的“Ａ”型图的“Ｘ”型图在解题中的应用．图形特征：ＤＥ截△ＡＢＣ两边（或两边的延长线）,且ＤＥ∥ＢＣ,由ＤＥ∥ＢＣ得　　ＡＤＡＥ＝ＤＢＥＣ＝ＡＢＡＣ,ＡＤＡＢ＝ＤＥＢＣ＝ＡＥＡＣ．证题方法：以平行线为桥梁,寻找或构造“Ａ”型图和“Ｘ”型图,探求解题思种．例１　已知：如图３,在△ＡＢＣ中,ＤＥ∥ＢＣ,ＢＥ与ＣＤ相交于点Ｏ,ＡＯ与ＤＥ、ＢＣ…     

怎样调节你的生物钟?

什么是生物钟:生物钟又称生理钟。它是生物体内的一种无形的“时钟”,实际上是生物体生命活动的内在节律性,它是由生物体内的时间结构顺序所决定。许多学者的研究指出,按照人的心理、智力和体力活动的生物节律,来安排一天、一周、一月、一年的作息制度,能提高工作效率和学习成绩,减轻疲劳,预防疾病,防止意外事故的发生。反之假如突然不按体内的生物钟的节律安排作息,人就会在身体上感到疲劳、在精神上感到不舒适。生物钟分几类:人体生物钟大致分三类:昼型、夜型、中间型。昼型表现为凌晨和清晨体力充沛,精神焕发,记忆力理解力最为出色,如数…     

四种动物型生物钟人群的一天

<正>睡眠时间跟每个人的生物钟有关,关于生物钟,经典的分类去是早睡早起"云雀型"和昼伏夜出"猫头鹰型"。但是美国睡眠专家、临床心理学家迈克尔·布鲁(Michael Breus)博士在此基础上将生物钟类型进一步细化,并选择了四种动物作为代表,它们分别是:狮子、熊、狼、海豚。     

人体内的生物钟

生物钟（人体内的天然时钟）是指隐藏在人体内的生物时间表,它会告诉人们什么时候应休息、睡眠,什么时候该活动、工作。人体内的生物钟以24小时为一个周期,这与脑内松果体的独特功能感光器作用有关。当天变暗时,分泌褪黑激素,引导人入睡;天亮时,又会停止分泌,以使人兴奋和活动。     

昆虫激素

激素是一些化学信息物质,这些化学物质只要少量存在就能引起重大的生理反应,而调节基本的生命活动,昆虫激素基本上可分为两大类:内激素和外激素。内激素或内分泌是由昆虫体内的腺体或组织所产生的化学信息物质,它们被分泌到体液内,借体液流动被带至全身,而对昆虫的生长和发育,起着控制和调节的作用。经过几十年的研究,目前已知对昆虫生长发育起作用的内分泌系统主要包括以下三种器官,即脑中的一群神经分泌细胞,紧位于脑后的小形白色腺体咽侧体,和位于前胸的前胸腺。     

Gain and Noise Properties of Bidirectional EDFAs

建立了考虑ＡＳＥ谱和背景损耗影响的双向掺铒光纤放大器（ＢｉＥＤＦＡ）稳态放大速率方程模型,分析了增益与掺铒光纤长度、输入信号光功率、泵浦光功率及泵浦方式等结构参数之间的关系,研究了单向和双向等功率泵浦下正反向噪声系数随正反向信号光输入功率的变化行为,所得结果可作为ＢｉＥＤＦＡ优化设计的理论依据     

同心圆问题的基本类型及解法

同心圆问题在近几年的中考试题中屡见不鲜 .这类问题的基本类型有两种 :一是大圆的弦与小圆相交或从大圆上一点引小圆的割线 ,即涉及小圆的割线问题 ;二是大圆的弦与小圆相切 ,即涉及小圆的切线问题 .解答前一类型的问题 ,常作的辅助线是作弦心距或小圆的切线 ;解答后一类型的问题常作的辅助线是作经过切点的半径 .例 1　如图 1 ,在以Ｏ为圆心的两个同心圆中 ,大圆的弦ＡＢ交小圆于Ｃ、Ｄ两点 .求证 :ＡＣ =ＢＤ .( 1 998年内蒙古自治区呼和浩特市中考题 )证明　过Ｏ作ＯＥ⊥ＣＤ于Ｅ ,则ＣＥ =ＤＥ .∵　ＯＥ⊥ＡＢ于Ｅ ,∴　ＡＥ =ＢＥ .…     

Act教学模式初探

在英语教学中,Ａｃｔ教学模式不仅是一种教学的方法,也是教学的内容和应达到的目标要求。该模式具有兴趣激发、目标导向、认知增效和信息调控等功能。在Ａｃｔ教学中要贯彻全员性、主体性、整体性和鼓励性等原则。其教学过程大致可归纳为感知、理解、巩固和运用４个阶段。     

中国民间剪纸与马蒂斯剪纸的比较

中国民间剪纸早期在实用功能上和马蒂斯的剪纸是完全不同的,前者是以实用功能为主;后者是以审美为主。这两者之间尽管有差异,同时也有着一定的相似性。因为,所用的材料都是纸和剪刀。它们都为绘画艺术的发展作出了贡献。     

EFFECTS OF JINLU, AN ANTI-JUVENILE HORMONE ON THE GROWTH, ULTRA-STRUCTURE OF THE CORPORA ALLATA AND PROTHORACIC GLAND OF SILKWORM, BOMBYX MORIL

ＩＮＴＲＯＤＵＣＴＩＯＮＩｎｓｅｃｔｐｏｓｔｅｍｂｒｙｏｎｉｃｄｅｖｅｌｏｐｍｅｎｔｃｏｎｓｉｓｔｓｏｆｇｒｏｗｔｈｐｕｎｃｔｕａｔｅｄｂｙａｓｅｒｉｅｓｏｆｍｏｌｔｓｆｏｌｌｏｗｅｄｂｙｍｅｔａｍｏｒｐｈｏｓｉｓ.Ｔｈｅｓｅｍｏｌｔｓａｎｄｍｅｔａｍｏｒ ｐｈｏｓｉｓａｒｅｉｎｉｔｉａｔｅｄａｎｄｃｏｏｒｄｉｎａｔｅｄｂｙｈｏｒｍｏｎｅｓ(Ｒｉｄｄｉｆｏｒｄ ,1 994 ) .Ｉｔｉｓｇｅｎｅｒａｌｌｙａｃｃｅｐｔｅｄｔｈａｔｔｈｅｉｎｔｅｒｐｌａｙｏｆｅｃｄｙｓｔｅｒｉｏｄｓ,ａｇｒｏｕｐｏｆｓｔｅｒｏ…     

TH—6040对两种食叶害虫的毒力测定及药效试验

设计了杀虫剂TH－6040对扬天社蛾和国槐尺蠖两食叶害虫的毒力测定和药效试验。试验结果表明：杀虫剂TH－6040对扬天社蛾的卵有较强的生物活性；该药剂对两食叶害虫的幼虫有较强毒力，是既经济又有效的常用农药。     

Complex patterns for kindergartners

Knowing what kinds of patterns are easy for children to recognize early in their kindergarten year, and what kinds are difficult, can be a useful guide for patterning instruction. Hence, the ability of children to recognize complex patterns early in their kindergarten year was assessed in two experiments. One experiment showed that the children were significantly less accurate on patterns made of progressively higher numbers or of letters that came progressively later in the alphabet than on patterns made of clock faces that showed increasing amounts of time or were made of rotating objects. There was an interaction between the type of element of which the pattern was composed and the pattern’s orientation. A second experiment showed that symmetric patterns were easier than growing patterns, and there were effects of orientation and the elements of which a pattern was composed, as well as interactions. This research indicates that instruction on clock faces and rotating objects should precede instruction on letters and numbers, and that symmetric patterns can also be easily understood.     

河北晋语区方言的儿化读音研究

河北属晋语区方言的共涉及35个县市,这些方言的儿化读音从类型上看都属于化合型的读音,但从具体音值上看,有单纯韵母变化型、混合变化型、边音韵尾型三种类型。与河北境内的官话相比,这些县市的儿化读音有两个突出特点:一是儿化韵数量较官话少,二是有些县市儿化韵的音值较特殊。究其原因,由于"儿"本身的读音差异和"儿"尾与"子"尾竞争导致的结果。     

狭义相对论中与实际观测有关的两个问题

详细讨论了狭义相对论里面两个极具启发性的问题,即观看运动的时钟和从小角度观看高速运动物体.说明了前者与狭义相对论中通常所说的"时间膨胀"之间的区别与联系,给出了运动时钟和静止时钟的时间间隔之间的关系.对后者,修正了前人讨论中的一处疏漏,从而说明在狭义相对论中涉及观看某现象时如何考虑光信号的传输限制.     

论家蚕传染病的综合防治

家蚕传染病的发生和蔓延,是由病原体侵染、蚕体的生理状况和环境条件等多方面因素共同作用的结果。本文根据各类蚕病发生规律,对家蚕传染性蚕病的综合防治措施进行了全面探讨。     

南瓜实蝇的产卵选择性研究

以南瓜、西葫芦、板栗瓜、姜柄瓜、黄瓜、香瓜6种果实引诱雌虫产卵结果可知,南瓜实蝇在姜柄瓜上引诱产卵最多(294粒)、次之为板栗瓜(37.67粒)、西葫芦(26.33粒)、香瓜(16.67粒)、南瓜(14.33粒)、而在黄瓜上引诱产卵最少(10.33粒).南瓜实蝇雌虫产卵喜欢在瓜肉面产卵.雌虫产卵易受果实伤口引诱,雌虫喜欢在人为损伤的伤口上产卵.     

Cryptochromes and biological clocks

Many of the biological activities of living organisms are light dependent and revolve around the solar clock. A variety of behaviours and physiological processes are under the control of internal biological clocks. These internal clocks are remarkably synchronized with the external solar clock (day-night cycle of 24 hour periodicity). The molecular mechanisms of biological clocks have recently been uncovered. Although there are several molecules, which have a key role to play in the functioning of biological clocks, cryptochromes have been implicated to be of special importance. A detailed study of cryptochromes may provide some answers to problems related to the abnormal functioning of biological clocks in humans.     

Ototoxic destruction by co-administration of kanamycin and ethacrynic acid in rats

It is well known that ethacrynic acid (EA) can potentiate the ototoxicity of aminoglycoside antibiotics (AmAn) such as kanamycin (KM), if they were applied at the same time. Currently, to create the model of EA-KM-induced cochlear lesion in rats, adult rats received a single injection of EA (75 mg/kg, intravenous injection), or followed immediately by KM (500 mg/kg, intramuscular injection). The hearing function was assessed by auditory brainstem response (ABR) measurement in response to click and/or tone bursts at 4, 8, 12, 16, 20, 24, and 32 kHz. The static microcirculation status in the stria vascularis after a single EA injection was evaluated with eosin staining. The pathological changes in cochlear and vestibular hair cells were also quantified after co-administration of EA and KM. After a single EA injection, blood flow in vessels supplying the stria vascularis rapidly diminished. However, the blood supply to the cochlear lateral wall partially recovered 5 h after EA treatment. Threshold changes in ABR were basically parallel to the microcirculation changes in stria vascularis after single EA treatment. Importantly, disposable co-administration of EA and KM resulted in a permanent hearing loss and severe damage to the cochlear hair cells, but spared the vestibular hair cells. Since the cochlear lateral wall is the important part of the blood-cochlea barrier, EA-induced anoxic damage to the epithelium of stria vascularis may enhance the entry of KM to the cochlea. Thus, experimental animal model of selective cochlear damage with normal vestibular systems can be reliably created through co-administration of EA and KM.